A washing machine is an apparatus that eliminates foreign matter or substances on or in laundry by agitating and/or rotating water, detergent, and the laundry together. Washing machines may be classified into a pulsator type washing machine that washes the laundry using a water flow generated by operation of a pulsator in a washing tub, and a drum type washing machine that rotates the drum to wash laundry by dropping the laundry vertically.
The drum type washing machine has a door that is at the front of the washing machine to place the laundry through the door. The rotating drum drops the laundry into the water and detergent to wash the laundry, and uses relatively small amounts of water and detergent. Specifically, a drum type washing machine in the related art includes a cabinet that forms an external appearance of the washing machine, a tub that is in the cabinet and that holds washing water, a rotatable drum that is in the tub and that accommodates or holds laundry, a drive motor that is installed on or near the tub and that provides power to rotate the drum, a water supply device that supplies water to the tub, and a water drain that discharges water from the tub to the outside of the cabinet (e.g., a drain pipe) after the washing operation(s) end.
Accordingly, according to the drum type washing machine in the related art, when the laundry is washed, the laundry is put into the tub in a lateral direction by opening a door at the front of the washing machine, water is supplied to the tub, and then the laundry is washed while a lifter in the drum lifts up and drops the laundry as the drum rotates by operation of the drive motor.
As such, the drum type washing machine in the related art includes the tub in addition to the drum. That is, the drum type washing machine in the related art has a structure that has the tub hold washing water and the drum in the tub rotate and wash the laundry.
However, because the tub is typically made of a plastic material, the tub may be easily contaminated by hard water, scale or other foreign substance(s) that enter the tub as the tub is used over a long period of time. There is a problem in that it is difficult to clean the tub because of the presence of the drum when the tub is contaminated. When the tub is contaminated, the tub becomes dirty, corroded, or a source of foreign substances and/or contaminants, and then the laundry becomes contaminated, which may cause irritation or skin problems or disease to the user.
This problem also occurs in pulsator type washing machines as well as drum type washing machines. Pulsator type washing machines also include a reservoir (tub) in the main body thereof.